Example Data Table
| Case |
Voltage |
Mode |
Resistors |
Capacitors |
Inductors |
Expected Use |
| Sensor divider |
5 V |
DC |
10k, 10k series |
None |
None |
Voltage divider planning |
| Audio filter load |
12 V |
AC at 1000 Hz |
220 parallel |
4.7 parallel |
10 series |
Reactance and phase estimate |
| Relay coil check |
24 V |
DC |
180 series |
None |
50 series |
Current and heat review |
Formula Used
Series resistance and inductance: R = R1 + R2 + R3 and L = L1 + L2 + L3.
Parallel resistance and inductance: 1 / Req = 1 / R1 + 1 / R2 + 1 / R3.
Capacitors: Parallel capacitance is added directly. Series capacitance uses 1 / Ceq = 1 / C1 + 1 / C2.
Reactance: XL = 2 × π × f × L. XC = 1 / (2 × π × f × C).
Impedance: Z = √(R² + (XL - XC)²). Current uses I = V / Z.
Power: Real power is I²R. Apparent power is VI. Reactive power is I²(XL - XC).
Stored energy: Capacitor energy is 0.5CV². Inductor energy is 0.5LI².
How to Use This Calculator
Choose DC for steady-state resistance checks. Choose AC when frequency, capacitance, inductance, impedance, and phase matter.
Enter resistor values in ohms, capacitor values in microfarads, and inductor values in millihenries. Separate values with commas.
Select series or parallel connection for each component group. Add wire resistance when leads, traces, or cables are important.
Press the calculate button. The result table appears above the form and below the header. Use CSV or PDF buttons to save the output.
Circuit Planning Guide
A circuit builder gives structure to early electrical work. It lets you test common component groups before making a physical layout. You can compare series paths, parallel paths, and reactive parts in one place. This helps avoid weak assumptions, oversized loads, and unsafe current levels.
Why This Tool Helps
Manual circuit checks are often simple, yet mistakes grow when many parts are involved. A resistor list may look small until equivalent resistance is reduced by a parallel branch. A capacitor group may store more energy than expected. An inductor may add strong reactance when frequency rises. The calculator brings these effects together and shows the final impedance, current, power, and phase.
Design Inputs
Start with the supply voltage. Then enter component values as comma separated lists. You can use plain numbers, or suffixes such as k, M, m, u, n, and p. Choose the connection style for each component group. Add wire resistance when leads, traces, or long conductors matter. Use tolerance to see how real components may shift the answer.
Reading The Results
The equivalent resistance shows the direct load path. The equivalent capacitance and inductance describe stored electric and magnetic energy. In alternating current mode, capacitive reactance subtracts from inductive reactance. The remaining reactance combines with resistance to form impedance. Current is then found from the supply voltage and impedance. Real power appears in the resistance. Reactive power appears in the stored energy exchange.
Practical Notes
Use the output as a planning guide, not as a final safety approval. Real boards include temperature rise, contact resistance, leakage, insulation limits, and device ratings. Motors, lamps, coils, and semiconductors can behave differently from simple ideal components. Always compare calculated current with fuse ratings, supply limits, and component data sheets.
Better Building Workflow
Build small sections first. Measure each group after assembly. Compare measured resistance or impedance with the calculator. When results differ, check wiring order, units, damaged parts, and meter range. Save the CSV or PDF output for design notes, repair records, classroom work, and later review. A clear record makes changes easier and reduces repeated mistakes during future circuit updates. Document assumptions, units, and chosen connection styles before sharing results with teammates or students each time.
FAQs
1. What does this circuit builder calculate?
It calculates equivalent resistance, capacitance, inductance, reactance, impedance, current, power, phase angle, energy storage, and tolerance ranges from your entered component lists.
2. Can I use kilo-ohm values?
Yes. You can enter values like 1k, 4.7k, or 2M for resistors. Plain resistor numbers are treated as ohms.
3. How are capacitor values entered?
Plain capacitor numbers are treated as microfarads. You can also use suffixes, such as n for nanofarads or p for picofarads.
4. Does DC mode use capacitors and inductors?
DC mode focuses on steady-state resistance and current. Reactive calculations are mainly shown in AC mode, where frequency affects capacitors and inductors.
5. Why does AC mode need frequency?
Capacitive and inductive reactance depend on frequency. Without frequency, the calculator cannot estimate AC impedance or phase behavior correctly.
6. What does safety factor mean?
The safety factor multiplies calculated current and power. It helps estimate a stronger design margin for parts, traces, wires, and supply capacity.
7. Is the PDF made without extra libraries?
Yes. The code creates a simple text PDF directly from calculated values. It avoids external document packages for easier installation.
8. Should this replace lab testing?
No. Use it for planning and comparison. Always verify important circuits with measurements, ratings, thermal checks, and proper safety practices.